2003 Monte Carlo SS

The last week or so i've been having problems with my A/C. Sometimes it works and sometimes it doesn't. When I start my car it may work right away at whatever speed the A/C is on, other times it may take 20-30 seconds before it actually engages. When the A/C doesn't start right away I can change the switches to different speeds but I cannot turn off the A/C and use the fan, use rear defrost, or anything else.

One thing I noticed is that when this happens the outside temp/direction module located with the sun roof switch doesn't come up either.

Any idea what is causing this?

 

Also, when the a/c isn't starting the odometer and the radio display are dim but one the a/c kicks in it brightens up.